JP2011188269A - High-output power amplifier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a high-output power amplifier capable of preventing reduction in output power which is synthesized and output, and suppressing expansion in device size when faults occur in some of a plurality of unit amplifiers connected in parallel. <P>SOLUTION: A distribution circuit 3 distributes an input wave from an input terminal 1. Each unit amplifier 4 has a power amplification circuit 9, circulators 10 and 11 provided before and behind the power amplification circuit, further, a fault detection circuit 12 and a drain voltage control circuit 13. If the fault detection circuit 12 detects a fault in one unit amplifier 4, a control circuit 8 commands the drain voltage control circuit 13 of another unit amplifier 4 to change a drain voltage, and the drain voltage control circuit 13 changes the drain voltage, thereby preventing power reduction in an output wave. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a high output power amplifier used in a communication device, a radar device, or the like.

  Amplifying elements used in power amplifiers have an upper limit on the amplification capacity depending on the element, so when power amplification exceeding the capacity of the amplifying elements is required, a plurality of unit amplifiers are combined in parallel to form a high output power amplifier. It has been made up. For example, Patent Document 1 adopts a redundant configuration with a unit amplifier in a start state and a unit amplifier in a stop state in preparation for a case where individual unit amplifiers constituting a high output power amplifier partially fail, There is disclosed a high output power amplifier that appropriately activates a unit amplifier that is in a stopped state when a failure occurs in the unit amplifier. Further, in Patent Document 2, in a high-output power amplifier constituted by two unit amplifiers, when both unit amplifiers are normal, a class A amplification operation is performed, and when one unit amplifier becomes abnormal, the other A high-output power amplifier that switches the unit amplifier to a class AB amplification operation is disclosed.

Japanese Patent Laid-Open No. 06-296115 JP 2002-50933 A

  In the case of the conventional high output power amplifier described in Patent Document 1, a unit amplifier in a stopped state is required in addition to a unit amplifier in an operating state, and in order to ensure higher reliability, the number of redundancy is increased. Therefore, there is a problem that the apparatus becomes large. On the contrary, there is a problem that if the number of redundancy is determined, it is not possible to cope with the number of failures beyond that. In the conventional high output power amplifier described in Patent Document 2, the efficiency is improved by changing the operation level of the unit amplifier by changing the gate voltage, but the output power is uniquely increased. Therefore, when the number of parallel unit amplifiers increases, there is a problem in that it is difficult to keep the output power combined and output constant corresponding to an arbitrary number of failures.

  The present invention can prevent a decrease in output power synthesized and output when a failure occurs in some unit amplifiers among a plurality of unit amplifiers connected in parallel, and suppresses an increase in the size of the device. An object of the present invention is to obtain a high-output power amplifier that can be used.

  A high output power amplifier according to the present invention includes a power amplifier circuit, first and second circulators connected to an input side and an output side of the power amplifier circuit, a failure detection circuit for detecting a failure of the power amplifier circuit, N unit amplifiers (N is an integer of 2 or more) having a drain voltage control circuit for controlling the drain voltage of the power amplifier circuit, and a distribution for distributing the input wave from the input terminal and outputting to the N unit amplifiers When a failure is detected by the circuit, a synthesis circuit for synthesizing the output waves of the N unit amplifiers, and when the failure is detected by the failure detection circuit, the power of the unit amplifier in which the failure is detected is stopped, And a control circuit for generating a control signal for instructing all or part of the drain voltage control circuits of the other unit amplifiers to increase the drain voltage.

  According to the present invention, the power supply of the unit amplifier in which the failure has occurred is stopped, and the drain voltage is controlled to be increased in all or a part of other unit amplifiers that are operating normally. And increase in size of the apparatus can be suppressed.

1 is a configuration diagram of a high-output power amplifier according to Embodiment 1 of the present invention. It is a schematic diagram showing the relationship between drain voltage and output electric power. It is a block diagram showing an example of a structure of a failure detection circuit. It is a block diagram showing another example of a structure of a failure detection circuit. It is a block diagram of the high output power amplifier which concerns on Embodiment 2 of this invention. It is a block diagram of the unit amplifier which comprises the high output power amplifier which concerns on Embodiment 3 of this invention. It is a block diagram showing another example of the unit amplifier which comprises the high output power amplifier which concerns on Embodiment 3 of this invention.

  Embodiment 1

  A high-output power amplifier according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 is a configuration diagram of a high-output power amplifier according to Embodiment 1 of the present invention. In FIG. 1, 1 is an input terminal, 2 is an output terminal, 3 is a distribution circuit for distributing an input wave from the input terminal 1, 4 is a unit amplifier, 5 is an input terminal to the unit amplifier 4, and 6 is an output of the unit amplifier. Reference numeral 7 denotes a synthesis circuit that synthesizes output waves from the unit amplifier 4, and 8 denotes a control circuit that controls the unit amplifier 4. In the unit amplifier 4, 9 is a power amplifier circuit, 10 is a circulator provided on the input side of the power amplifier circuit 9, 11 is a circulator provided on the output side of the power amplifier circuit 9, and 12 is a failure of the power amplifier circuit 9. A failure detection circuit 13 for detecting a drain voltage control circuit 13 controls the drain voltage of the power amplifier circuit 9. In FIG. 1, the reference numerals 1 and 2 are continuously added to the reference numerals of the unit amplifier 4 and the like to indicate that the respective components or circuits are included in the circuit system 1 and the circuit system 2 (hereinafter referred to as “the unit amplifier 4”). The same applies to the drawings in FIG.

  Next, normal operation will be described. The distribution circuit 3 distributes the high frequency input from the input terminal 1 into two. The unit amplifier 4 inputs the input wave distributed by the distribution circuit 3 to the power amplifier circuit 9 via the circulator 10, amplifies it, and then outputs it via the circulator 11. The output wave amplified by each unit amplifier 9 is synthesized by the synthesis circuit 7 and output from the output terminal 2. Here, the drain voltage of the power amplifier circuit 9 is set to a predetermined voltage by the drain voltage control circuit 13 so as to obtain a desired output wave power. FIG. 2 is a schematic diagram showing the relationship between the drain voltage Vd set by the drain voltage control circuit 13 and the output power Pout (for one unit amplifier 4), so that the drain voltage can be increased at the time of failure as will be described later. The operating point A during normal operation is set.

  Next, the operation when a failure occurs in one of the unit amplifiers 4 will be described. In the unit amplifier 4 of one circuit system, the failure detection circuit 4 outputs a failure detection signal to the control circuit 8 when detecting a failure of the power amplifier circuit 9. Upon receiving the failure detection signal, the control circuit 8 turns off the power of the power amplifier circuit 9 of the unit amplifier 4 that has failed, and increases the drain voltage of the power amplifier circuit 9 of the unit amplifier 4 that is operating normally. A control signal to be commanded is generated and output to the drain voltage control circuit 13 in the unit amplifier 4 operating normally. The drain voltage control circuit 13 receives this control signal and increases the drain voltage of the power amplifier circuit 9 of the unit amplifier 4. Specifically, as shown in FIG. 2, the drain voltage is increased to change the setting from point A to point B. With this setting change, the output power of the power amplifier circuit 9 of the unit amplifier 4 operating normally increases by 3 dB, and the power of the output wave from the output terminal 2 can maintain the value before the failure. The point B is preferably set in advance in a region where the output power does not saturate and the distortion is small, and a point A whose output power is 3 dB lower than the point B may be set for normal operation. Actually, the number of circuit systems is an integer of 2 or more so that the point B can be set and the point A can be set based on the magnitude of the required output power and the drain voltage vs. output power characteristics of the power amplifier circuit 9 to be used. You can decide.

  On the other hand, regarding the failed unit amplifier 4, when there are no circulators 10 and 11, in general, the input / output impedance of the power amplifier circuit 9 is in an open or short-circuited state, as seen from the distribution circuit 3 side and the synthesis circuit 7 side. The unit amplifier 4 which is in the total reflection state and operates normally is affected. As shown in FIG. 1, by providing circulators 10 and 11 on the input side and output side of the power amplifier circuit 9, respectively, total reflection at the failed power amplifier circuit 9 can be prevented, and the input / output impedance can be kept constant. it can.

  Next, the configuration and operation of the failure detection circuit 12 will be described with reference to FIGS. In FIG. 3, the failure detection circuit 12 includes a power distributor 14 and an RF power detector 15. The high frequency amplified by the power amplifier circuit 9 in the unit amplifier 4 is output from the output terminal 6 via the circulator 11, but a part of the power is distributed by the power distributor 14 and input to the RF power detector. . The power is monitored by the power detector 14, and if it is outside the specified power range, it is determined that there is an abnormality, and the control circuit 8 is notified. The circulator may be an isolator.

  FIG. 4 shows another example of the failure detection circuit 12, and the failure detection circuit 12 is constituted by a current value detection circuit 16. The drain voltage application state of the power amplifier circuit 9 is monitored by a current value detection circuit 16 which is a so-called ammeter. If the current value is outside the specified range, it is determined that there is an abnormality, and the control circuit 9 is notified.

  After a failure occurs in one of the circuit systems and the drain voltage of the power amplifier circuit 9 operating normally as described above is changed, an abnormal operation in the failure detection circuit 12 of the unit amplifier 4 during normal operation is detected. The specified range of the power value and current value used for the determination may be changed.

  As described above, when one of the two system unit amplifiers 4 fails, the output voltage is increased by increasing the drain voltage of the power amplifier circuit 9 on the non-failed side, so that the output at the output terminal 2 is increased. The power can be prevented from decreasing, and the operation up to the replacement / repair of the failed part can be continued. Further, as compared with the configuration of a conventional high output power amplifier using a redundant system, a spare system is unnecessary, and the size can be reduced.

  Embodiment 2

  A high-output power amplifier according to Embodiment 2 of the present invention will be described with reference to FIG. As shown in FIG. 5, the high-output power amplifier according to the second embodiment has N unit amplifiers (N is an integer of 2 or more) connected in parallel. However, since the case where N = 2 has already been described in the first embodiment, the case where N is 3 or more is a target in the second embodiment. In FIG. 2, the reference numerals 1 to N are continuously added to the reference numerals of the unit amplifier 4 and the like to indicate that the respective components or circuits are included in the circuit systems 1 to N. Except as specifically described below as the second embodiment, components and circuits denoted by the same reference numerals as those in FIG. 1 in FIG. 5 represent components and circuits that are the same as or equivalent to those components and circuits in FIG. In addition, the failure detection circuit 12 according to the second embodiment is equivalent to the circuit configuration illustrated with reference to FIGS. 3 and 4 in the first embodiment, and therefore its description is omitted for the sake of brevity.

  In a state where all the unit amplifiers 4 are operating normally, the input wave distributed N by the distribution circuit 3 is input to the power amplification circuit 9 via the circulator 10 in each unit amplifier 4, and the power amplification circuit 9 The input wave is amplified and output to the synthesis circuit 7 via the circulator 11. The synthesis circuit 7 synthesizes output waves from the N system unit amplifiers 4, and the synthesized output wave is output from the output terminal 2. Further, it is assumed that the drain voltage of the power amplifier circuit 9 is set to the operating point A shown in FIG.

  Next, the operation at the time of failure will be described. When one unit amplifier 4 out of the N unit amplifiers 4 fails, the failure detection circuit 12 in the failed unit amplifier 4 detects a failure and outputs a failure detection signal to the control circuit 8. Upon receiving the failure detection signal, the control circuit 8 turns off the power of the power amplifier circuit 9 of the unit amplifier 4 that has failed, and increases the drain voltage of the power amplifier circuit 9 of the unit amplifier 4 that is operating normally. A control signal to be commanded is generated and output to the drain voltage control circuit 13 in the unit amplifier 4 operating normally. The drain voltage control circuit 13 receives this control signal and increases the drain voltage of the power amplifier circuit 9 of the unit amplifier 4.

  Further, even when m unit amplifiers 4 out of N unit amplifiers 4 (m is an integer smaller than N) fail, a failure is detected by the failure detection circuit 12 in each failed unit amplifier 4 and is controlled. The circuit 8 turns off the power supply of the power amplifier circuit 9 of the unit amplifier 4 in the failed state, and increases the drain voltage of the power amplifier circuit 9 in the unit amplifier 4 operating normally.

  Here, regarding the method of increasing the drain voltage of the power amplifier circuit 9 of the unit amplifier 4 that is operating normally, the control circuit 8 takes a more efficient method depending on the configuration of the distribution circuit 3 and the synthesis circuit 7. become. First, consider a case where the distribution circuit 3 and the synthesis circuit 7 have a tournament-type circuit configuration in which two distributors are connected in series and parallel. In this case, the output of the (k−1) -th or k + 1-th unit amplifier 4 (the other unit amplifier 4 of the 2-distributor / combiner to which the failed unit amplifier 4 is connected) paired with the failed k-th unit amplifier 4. By changing the setting to increase the drain voltage of the k−1th or k + 1th unit amplifier 4 so that the power of the wave is doubled (setting change to the operating point B in FIG. 2), the combined loss is reduced. Can be minimized.

  On the other hand, when the distribution circuit 3 and the synthesis circuit 7 are configured by the collective multi-branch method, the drain voltage is set and changed so that all output powers of the unit amplifier 4 operating normally increase uniformly. That's fine. The output power of each unit amplifier 4 at this time is set to N / (N−m) times the output power in the normal state.

  As described above, according to the high output power amplifier according to the second embodiment of the present invention, it is possible to suppress a decrease in output power of the high output power amplifier even in a mode in which a plurality of unit amplifiers 4 fail. It is. Similarly to the first embodiment, each unit amplifier 4 has circulators 10 and 11 before and after the power amplifier circuit 9, and the input / output of the unit amplifier 4 regardless of the normal / failure state of the power amplifier circuit 9. The impedance can be fixed by the characteristics of the circulators 10 and 11. In addition, since the input / output impedance of the unit amplifier 4 can be fixed, the number of the unit amplifier 4 that fails, the number of the unit amplifier 4 that increases the drain voltage at the time of the failure, and the drain voltage setting change value are determined in advance. If it is stored in the control circuit 8, efficient operation can be continued while minimizing the increase in output power due to the change in the drain voltage setting of the unit amplifier 4 operating normally.

  Embodiment 3

  A high-output power amplifier according to Embodiment 3 of the present invention will be described with reference to FIGS. FIG. 6 and FIG. 7 are configuration diagrams showing another embodiment of a unit amplifier that constitutes a high-output power amplifier. The overall configuration of the high output power amplifier according to the third embodiment is the same as that shown in FIG. 1 or FIG. 2 described in the first or second embodiment. It becomes a configuration substituted by. Therefore, except for what is specifically described for the unit amplifier 4 and the like in the third embodiment, it is configured and operates in the same manner as that described in the first and second embodiments with reference to FIGS. The explanation is omitted for the sake of brevity.

  In the configuration example of the unit amplifier 4 shown in FIG. 6, 17 is a main amplifier, and 18 is a sub-amplifier, which are connected in parallel to form the power amplifier circuit 9. The operation of the power amplifier circuit 9 will be described. The main amplifier 17 and the sub-amplifier 18 are different in operating point, and such a parallel-connected amplifier circuit configuration is generally called a Doherty configuration. Specifically, the main amplifier 17 is a peak amplifier that operates in class C, and the sub-amplifier 18 is a carrier amplifier that operates in class A, class AB, or class B. In order to obtain a Doherty configuration, a quarter wavelength line is inserted on the output side of the carrier amplifier and a 90-degree phase shifter is inserted on the input side of the peak amplifier, but the illustration is omitted.

  Since the power amplifier circuit 9 of the unit amplifier 4 has a Doherty configuration as shown in FIG. 6, the efficiency can be increased in a device that requires high output and back-off from saturated power. It is suitable for a high output power amplifier that increases the output power by increasing the drain voltage of the unit amplifier that is operating normally at the time of failure, and prevents the overall output wave power from being lowered.

  The failure detection circuit 12 for detecting such a failure of the Doherty amplifier circuit will be described. In the case of the failure detection circuit 12 shown in FIG. 3, the failure detection circuit 12 can be similarly configured in the subsequent stage of the circulator 11. In the case of the failure detection circuit 12 shown in FIG. 4, the drain voltage application state is monitored for each of the main amplifier 17 and the sub-amplifier 18 by the current value detection circuit 16 which is a so-called ammeter, and if the current value is outside the specified range. What is necessary is just to determine that it is abnormal and to notify the control circuit 9.

  Next, in the configuration example of the unit amplifier 4 shown in FIG. 7, reference numeral 19 denotes a phase variable circuit. The phase variable circuit 19 is provided before the power amplifier circuit 9 and provided on the input terminal 5 side of the circulator 10. It is. The operation of this unit amplifier 4 will be described. As described in the second embodiment, when a failure occurs in any of the N unit amplifiers 4, the drain voltage of the other unit amplifiers 4 operating normally can be arbitrarily set by the drain voltage control circuit 13. By increasing it, it is possible to prevent a decrease in power at the output terminal 2 of the high output power amplifier. This is to control the amplitude of the output wave, but according to the configuration of the unit amplifier 4 shown in FIG. 7, the phase is also controlled by loading the phase variable circuit 19 in the previous stage of the power amplifier circuit 9. It is.

  When a failure occurs in the m unit amplifiers 4, the amount of increase in the drain voltage and the output phase of other N−m unit amplifiers 4 operating normally depend on the configurations of the distribution circuit 3 and the synthesis circuit 7. To do. Therefore, similarly to the second embodiment, not only the amplitude but also the phase can be controlled corresponding to a plurality of failure modes, and the optimum operation is possible. Further, since the input / output impedance of the failed unit amplifier 4 is fixed by the circulators 10 and 11, the number of the unit amplifier 4 that fails, the number of the unit amplifier 4 that increases the drain voltage at the time of the failure, and the drain voltage thereof If the setting change value and the phase setting change value of the phase variable circuit 19 are determined and stored in the control circuit 8, the output power increases with the setting change of the drain voltage of the unit amplifier 4 operating normally. It is possible to continue efficient operation while minimizing.

DESCRIPTION OF SYMBOLS 1 Input terminal 2 Output terminal 3 Distribution circuit 4 Unit amplifier 7 Synthesis circuit 8 Control circuit 9 Power amplifier circuit 10, 11 Circulator 12 Failure detection circuit 13 Drain voltage control circuit 14 Power divider 15 RF power detector 16 Current value detection circuit 17 Main amplifier 18 Sub-amplifier 19 Phase variable circuit

Claims (5)

A power amplifier circuit; first and second circulators connected to an input side and an output side of the power amplifier circuit; a failure detection circuit that detects a failure of the power amplifier circuit; and a drain that controls a drain voltage of the power amplifier circuit N unit amplifiers having a voltage control circuit (N is an integer of 2 or more), a distribution circuit that distributes an input wave from an input terminal and outputs it to the N unit amplifiers, and the N unit amplifiers When a fault is detected by the synthesis circuit for synthesizing the output wave and the fault detection circuit, the power supply of the unit amplifier in which the fault is detected is turned off, and the drain voltage control of other unit amplifiers operating normally A high output power amplifier comprising: a control circuit that generates a control signal that commands all or part of the circuit to increase the drain voltage. 2. The high output according to claim 1, wherein the failure detection circuit detects a failure by monitoring power with a power detector connected to an output terminal of the second circulator via a power distributor. Power amplifier. 2. The high output power amplifier according to claim 1, wherein the failure detection circuit detects a failure by monitoring a drain current of the power amplification circuit. 4. The high output power amplifier according to claim 1, wherein the power amplifier circuit is a Doherty amplifier. 5. The high-output power amplifier according to claim 1, wherein the unit amplifier includes a phase variable circuit on an input side of the first circulator.

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